Insights from Overviewing Selective International Guidelines for Pediatric Asthma.

BACKGROUND: Asthma is a chronic atopic and inflammatory bronchial disease characterized by recurring symptoms and, episodic reversible bronchial obstruction and easily triggered bronchospasms. Asthma often begins in childhood. International guidelines are widely accepted and implemented; however, there are similarities and differences in the management approaches. There is no national guideline in many cities in Asia. This review aims to provide a practical perspective on current recommendations in the management of childhood asthma, specifically in the following aspects: diagnosis, classification of severity, treatment options, and asthma control, and to provide physicians with up-to-date information for the management of asthma. METHODS: We used the PubMed function of Clinical Queries and searched keywords of "Asthma", "Pediatric," AND "Guidelines" as the search engine. "Clinical Prediction Guides", "Etiology", "Diagnosis", "Therapy," "Prognosis," and "Narrow" scope were used as filters. The search was conducted in November 2022. The information retrieved from this search was used in compiling the present article. RESULTS: Diagnosis is clinically based on symptom pattern, response to therapy with bronchodilators and inhaled corticosteroids, and spirometric pulmonary function testing (PFT). Asthma is classified in accordance with symptom frequency, peak expiratory flow rate (PEFR), forced expiratory volume in one second (FEV1), atopic versus nonatopic etiology, where atopy means a predisposition toward a type 1 hypersensitivity reaction. Asthma is also classified as intermittent or persistent (mild to severe). Unfortunately, there is no disease cure for asthma. However, symptoms can be prevented by trigger avoidance and suppressed with inhaled corticosteroids. Antileukotriene agents or long-acting beta-agonists (LABA) may be used together with inhaled corticosteroids if symptoms of asthma are not controlled. Rapidly worsening symptoms are usually treated with an inhaled short-acting beta-2 agonist (SABA, e.g., salbutamol) and oral corticosteroids. Intravenous corticosteroids and hospitalization are required in severe cases of asthma attacks. Some guidelines also provide recommendations on the use of biologics and immunotherapy. CONCLUSION: Asthma is diagnosed clinically, with supporting laboratory testing. Treatment is based on severity classification, from intermittent to persistent. Inhaled bronchodilator and steroid anti-inflammatory form the main stay of management.

Childhood pertussis is still here: An Asian city's perspectives.

INTRODUCTION: Pertussis, or whooping cough, is a highly contagious respiratory infection that is caused by the bacterium Bordetella pertussis. It is one of the most common causes of death in childhood. It is also a frequent cause of chronic cough in children, adolescents, and adults. METHODS: Global and Hong Kong perspectives of childhood pertussis were described. RESULTS: Hong Kong has prided herself in the city's childhood immunization program. There appear to be no major outbreaks of pertussis since the 1960s. Nevertheless, pediatricians may see isolated cases of pertussis or pertussis-like cases from time to time. Occasionally, infants are severely affected with apneas and managed with ventilator supports in the PICU. Outbreaks of the notifiable disease continue to occur despite a reasonable surveillance system and vaccination program in Hong Kong. Vaccination of mothers, adolescents, and adults are efficacious methods to further reduce the risks of pertussis. Macrolides remain efficacious antibiotics especially used early during the infectious phase. Infants with pertussis may require intensive care support and morbidity is high. CONCLUSIONS: Physicians should be reminded from time to time that outbreaks of pertussis still exist in Hong Kong and in many cities globally.

Synchronized abdominal compression as a novel treatment of life-threatening preschool asthma.

Introduction: In severe asthma, management of life-threatening air trapping that persists despite initiation of standard asthma treatment is difficult in the absence of extracorporeal membranous oxygenation.Case study: Three children with life-threatening asthma could not be adequately ventilated despite maximum conventional treatment because of severe air trapping. A novel method of active expiration by abdominal compression with a standard ventilator was adopted with immediate effect with significant improvement in ventilation.Conclusion: Synchronized abdominal compression is a novel and simple method that allows an effective treatment of severe air trapping in an intubated paralyzed asthma child.

Orthodontic plate for management of obstructive sleep apnoea in infants with Pierre Robin sequence: experience and protocol in Hong Kong.

OBJECTIVE: To present the application of the pre-epiglottic baton plate (PEBP) in infants with Pierre Robin sequence (PRS) in the Southern Chinese population (Hong Kong) and to present the diagnosis and management protocol of these infants in our centre. DESIGN: Retrospective case series of three patients with PRS. SETTING: Neonatal Intensive Care Unit in Kwong Wah Hospital and Craniofacial Orthodontic Centre in United Christian Hospital, Hong Kong. PARTICIPANTS: Three new-born infants (two girls, one boy) with PRS and upper airway obstruction due to glossoptosis. METHODS: A protocol for the diagnosis and management of these infants in the Southern Chinese population (Hong Kong) was presented. The three patients received nasal high-flow oxygen and/or continuous positive airway pressure (CPAP) as first-line respiratory support, followed by PEBP for 3-5 months. A two-stage approach was undertaken to ensure accurate positioning of the PEBP. RESULTS: All three infants had improvement in clinical signs, symptoms and polysomnography upon discharge. PEBP and other respiratory aids were weaned off at 3-6 months. CONCLUSIONS: The PEBP, combined with other respiratory support, is a useful modality in the treatment of obstructive sleep apnoea in infants with PRS.

Determinants for asthma control, quality of life and use of complementary and alternative medicine in asthmatic pediatric patients in four cities.

BACKGROUND: Asthma is a significant chronic health problem worldwide. Management aims at disease control by reducing functional impairment and exacerbations and improving quality of life (QoL). We report a multi-center study to survey asthma control and QoL in four cities in the Pearl River Delta. METHODS: The conjoint survey involved ten Hong Kong pediatric hospitals/units, two Shenzhen hospitals, two Macau hospitals, and two Guangzhou hospitals on asthma control (using Asthma Control Test) and QoL (Pediatric Allergic Disease Quality of Life Questionnaire, PADQLQ). Acceptability of a treatment is graded as very good/good/fair/poor. RESULTS: Good asthma control was only reported in 80% subjects in Hong Kong, but higher in sister cities (85-94%, P < 0.001). Allergic rhinitis, "incense burning", and "smoker in family" were prevalent among the four cities. Logistic regression showed better control of asthma was associated with better PADQLQ (B = - 0.029, P < 0.001), better acceptability of bronchodilator (B = - 1.488, P = 0.025), negatively with "smoker in family" (B = - 0.83, P = 0.015) and various PADQLQ domains. Conversely, worse PADQLQ was associated with allergic rhinitis severity (B = 4.77, P < 0.001), poor control of asthma (B = 7.56, P < 0.001), increased frequency of traditional Chinese medicine use (B = 1.7, P < 0.05), increased frequency of bronchodilator usage (B = 1.05, P < 0.05), "smoker in family" (B = 4.05, P < 0.05), and incense burning at home (B = 3.9, P < 0.05). CONCLUSIONS: There are some clinical and cultural differences among the four southern Chinese cities within the Guangdong province. This study identifies potentially modifiable environmental and treatment factors associated with poor asthma control and QoL for health-care interventions. Having a smoker in the family is independently associated with poor asthma control and QoL.

A community-based cross-sectional immunisation survey in parents of primary school students.

Immunisation is a very important aspect of child health. Invasive pneumococcal and influenza diseases have been major vaccine-available communicable diseases. We surveyed demographics and attitudes of parents of primary school students who received pneumococcal conjugate vaccination (PCV) and compared them with those who did not receive pneumococcal vaccination. The survey was carried out in randomly selected primary schools in Hong Kong. Questionnaires were sent to nine primary schools between June and September 2014. Parents of 3,485 children were surveyed, and 3,479 (1,452 PCV immunised, 2,027 un-immunised) valid questionnaires were obtained. Demographic data were generally different between the two groups. PCV-immunised children were more likely to be female (57.0 vs. 52.2%, P=0.005), born in Hong Kong (94.2 vs. 92.3%, P=0.031), have a parent with tertiary education (49.2 vs. 31.8, P<0.0005), from the higher-income group (P=0.005), have suffered upper respiratory infections, pneumonia, otitis media or sinusitis (P=0.019), and have doctor visits in preceding 12 months (P=0.009). They were more likely to have received additional immunisations outside the Hong Kong Childhood Immunization Programme (64.0 vs. 30.6%, P<0.0005) at private practitioner clinics (91.1 vs. 83.5%, P<0.0005). Un-immunised children were more likely to live with senior relatives who had not received PCV. Their parents were less likely to be aware of public education programme on PCV and influenza immunisation, and children were less likely to have received influenza vaccination. The major reasons for PCV immunisations were parent awareness that pneumococcal disease could be severe and vaccines were efficacious in prevention. The major reasons for children not being immunised with PCV were concerns about vaccine side effects, cost, vaccine not efficacious or no recommendation by family doctor or government. In conclusion, PCV unimmunized children were prevalent during the study period. Reportedly, they were generally less likely to have received influenza and other childhood vaccines, and more likely to live with senior relatives who had not received PCV and influenza. These observations provide important demographic data for public health policy in childhood immunisation programme.

Prevalence of otitis media with effusion in children with allergic rhinitis, a cross sectional study.

OBJECTIVES: Otitis media with effusion (OME) may be caused by various factors including Eustachian tube dysfunction, inflammatory response as well as atopy. Allergic rhinitis (AR), a common chronic disorder in children, is associated with swelling of the mucosa and can therefore result in Eustachian tube dysfunction. This study aims to compare the prevalence of OME in subjects with and without AR. METHOD: Children aged 4-12 were recruited from the clinics at Kwong Wah Hospital, Hong Kong. Subjects recruited were interviewed and a questionnaire filled in regarding nasal obstruction, rhinorrhea, sneezing, itching of the nose and/or post nasal discharge (ARIR document). The children were then examined by a doctor using a pneumatic otoscopy and a portable tympanometer. Children found to have OME were offered a follow-up visit 3 months later. RESULTS: 12 out of 159 (7.5%) of the AR group were found to have OME compared with 3 out of 185 (1.6%) in the non-AR group, p=0.016. During the 2nd visit at 3 months, 85.7% of the AR subjects showed resolution of their OME. CONCLUSIONS: Our data showed a significant difference in the prevalence of OME between AR and non-AR subjects. Of the 185 non AR subjects (Control group), 3 was found to have OME, suggesting a point prevalence of OME of 1.6% in the community in Hong Kong. OME is more likely to occur in children with allergic rhinitis and it may be wiser to manage OME in these individuals differently.

Central Hypoventilation: A Case Study of Issues Associated with Travel Medicine and Respiratory Infection.

Aim. We presented the case of a child with central hypoventilation syndrome (CHS) to highlight issues that need to be considered in planning long-haul flight and problems that may arise during the flight. Case. The pediatric intensive care unit (PICU) received a child with central hypoventilation syndrome (Ondine's curse) on nocturnal ventilatory support who travelled to Hong Kong on a make-a-wish journey. He was diagnosed with central hypoventilation and had been well managed in Canada. During a long-haul aviation travel, he developed respiratory symptoms and desaturations. The child arrived in Hong Kong and his respiratory symptoms persisted. He was taken to a PICU for management. The child remained well and investigations revealed no pathogen to account for his respiratory infection. He went on with his make-a-wish journey. Conclusions. Various issues of travel medicine such as equipment, airline arrangement, in-flight ventilatory support, travel insurance, and respiratory infection are explored and discussed. This case illustrates that long-haul air travel is possible for children with respiratory compromise if anticipatory preparation is timely arranged.

Complementary and alternative medicine for childhood asthma: an overview of evidence and patents.

Asthma is a prevalent childhood atopic disease associated with significant impairment of quality of life. Management relies on avoidance of triggers such as food and aeroallergens, the use of inhaled bronchodilators/corticosteroids and anti-allergic or immune-modulating therapies. Inhaled corticosteroids (ICSs) and bronchodilators have been the mainstay of treatment. In China as well as throughout Asia, myths and misconceptions on western medicine and corticosteroids are prevalent and result in non-adherence of treatment. A wide variety of complementary and alternative medicines (CAM) are available. Some of these have undergone extensive clinical trials and have been documented to have some therapeutic effects on asthma. Nevertheless, the majority of these treatment modalities is not efficacious and may even be detrimental. This article overviews the evidence for the clinical efficacy of all major CAM modalities. Despite CAM modalities are extensively used by the patients with asthma, very few CAM patents are available. This article also discusses recent patents pertinent to asthma. Only a few patents on herbal medicine for asthma have been evaluated but therapeutic efficacy is not substantially documented. Parents seeking CAM for asthma must consult qualified registered practitioners before using it.

Natural history of snoring in Hong Kong adolescents.

AIM: To determine the natural history of snoring in children when they reached adolescence and the underlying risk factors for persistence of habitual snoring. METHODS: A follow-up telephone survey was conducted to determine the natural history of snoring in children who reached adolescence. The targeted interviewees of the follow-up survey were parents of 3047 children. Adolescents who were snoring ≥6 nights a week were defined as habitual snorers. Potential risk factors for persistent and incident habitual snoring were studied, including age, gender, allergic rhinitis, asthma, body mass index (BMI), sleep duration and daytime sleepiness. RESULTS: Of the 3047 subjects, 2005 (65.8%) were successfully interviewed by phone. The prevalence of habitual snorers was 12.7%. Ninety-one adolescents were persistent habitual snorers. Allergic rhinitis, male gender and higher BMI at follow-up were identified as significant risk factors for persistent habitual snoring. A further 163 children were identified as incident habitual snorers. The risk factors for incident habitual snoring included male gender, asthma, higher BMI at follow-up and younger age at the first survey. In the current study, the mean sleep duration was 7.6 ± 1.0 h. Overall, 90% of the current cohort slept less than the lower limit of international recommendations for sleep duration. CONCLUSIONS: Around 40.6% of habitually snoring children continued to snore habitually as adolescents in the current study, while 9.2% of the initial non-habitual snorers became habitual snorers. Male gender and higher BMI were significant risk factors for both persistent and incident habitual snoring.

A review of normal values of infant sleep polysomnography.

BACKGROUND: The objective of this study was to summarize current information about the normal values on infant sleep polysomnography for clinical use. METHODS: MEDLINE (Ovid), EMBASE (Ovid), and CINAHL (Ovid) from January 1976 to May 2007 were searched. Two reviewers independently reviewed all relevant articles, using preset inclusion criteria. The population of interest included children aged less than 1 year. Studies in infants with known major anomalies were excluded. The results on apneas were extracted and analyzed. RESULTS: For obstructive apnea, the upper limit of normal values was less than 1.0 per hour, and for mixed apnea, the current data suggested the upper limit of normal values was less than 1.0 per hour. For central apnea defined as cessation of respiratory efforts for more than 3 seconds, the current data suggested that the upper limit of the normal central apnea index was 45 per hour for 1-month-old infants, 30 per hour for 2-month-old infants, 22 per hour for 3-month-old infants, and between 10 and 20 for the older age groups. For the desaturation episode defined as SpO2 less than 80% for any length of time, the current data suggested the upper limit of normal values to be 14.7 episodes per hour for day 1, 41 episodes for day 4, and 15.1 episodes for day 39. CONCLUSION: The normal values of obstructive apnea, mixed apnea, and central apnea are well established for neonates and infants. With these normal values, sleep polysomnography study should be routinely used to quantify the severity of breathing disorders during sleep in those neonates at risk for these disorders.

Validation of sleep-related breathing disorder scale in Hong Kong Chinese snoring children.

The purpose of this study is to validate the previously-validated Taiwan Chinese version of Sleep-Related Breathing Disorder scale (SRBD scale) in Hong Kong Chinese snoring children. SRBD scale is an instrument used for prediction of obstructive sleep apnea syndrome. (OSA) The Chinese version of SRBD scale were previously translated and validated in Taiwan. The same questionnaire were administered in a group of 102 snoring children (mean age: 10.7 and 65 boys) from a sleep laboratory in Hong Kong before their sleep studies. The SRBD scores were then validated against the results from sleep studies. By using the definition of apnea-hypopnea index larger than 1.5 as OSA, 28 children (27.5%) had polysomnography-confirmed OSA. The sensitivity, specificity, positive likelihood ratio and negative likelihood ratio of the previously validated cut-off of SRBD score > 0.33 for OSA were 0.5, 0.55, 1.12, and 0.90, respectively. The area under ROC curve was only 0.58, indicates suboptimal performance of SRBD score in predicting OSA. In summary, our study concluded that the previously reported Chinese SRBD scale is not accurate in identifying presence of OSA in Hong Kong Chinese snoring children.

Gender difference in snoring and how it changes with age: systematic review and meta-regression.

PURPOSE: The aim of this study was to study the interactions among age, gender, and snoring across all age groups METHODS: All cross-sectional study reporting gender-specific prevalence of snoring in general population published from 1966 through July 2008 were included and were meta-analyzed. The sources of heterogeneity among primary studies were studied by meta-regression. RESULTS: From a total of 1,593 citations reviewed, 63 were included in the analysis of snoring. These 63 studies were comprised 104,337 and 110,474, respectively. A combined odds ratio of 1.89 with a 95% confidence interval of 1.75-2.03 for male versus female was found. The heterogeneity was significant with an estimated between-study variance, τ (2) being 0.065 and 95% confidence interval of 0.0397-0.0941. Multiple meta-regression showed that age were the significant effect modifier of the relationship between snoring and gender. CONCLUSION: This study found a consistent male predominance in snoring among the general population, and the heterogeneity in the risk of snoring between two genders can be partly explained by age.

Risk factors for post-operative complications in Chinese children with tonsillectomy and adenoidectomy for obstructive sleep apnea syndrome.

PURPOSE: Tonsillectomy and adenoidectomy (T&A) is commonly performed in children with obstructive apnea syndrome (OSAS). It was our hospital practice to observe all patients post T&A in the pediatric intensive care unit. We aim to describe the post-operative complications after tonsillectomy and adenoidectomy in children with OSAS and to identify risk factors for these complications. METHOD: Medical records of patients from 1 to 16 years old with OSAS and T&A done in this department were retrieved for analysis from April 1999 to July 2006. Information of the individual patients including the demographic data, polysomnography data, and presence of post-operative complications were recorded and analyzed. RESULTS: A total of 86 patient records were analyzed (M/F = 69:17). The mean BMI z score was 1.13 ± 1.53, and 36% of patients were classified as obese with z > 1.96. The median apnea-hypopnea index (AHI) before T&A was 9.8 episodes/h. Only six patients had post-operative desaturation. No bleeding complications were reported in our cohort. It was found that patients with desaturation after T&A had significantly higher mean BMI z score than children without desaturation (p = 0.014). There was otherwise no significant difference between the age, sex, AHI score, and the history of allergic rhinitis or asthma between the two groups. CONCLUSION: Our results showed that most children with OSAS underwent T&A without complications. The respiratory complication rate was 7%, and desaturation was the most common post-operative complication. Children with higher BMI z score were more likely to have desaturation after T&A (p = 0.014). Hence, careful monitoring with pulse oximeter after T&A should be offered to those who are obese.

Development of the Chinese version of the Paediatric Allergic Disease Quality of Life Questionnaire: reliability and validity.

OBJECTIVE: Paediatric Allergic Disease Quality of Life Questionnaire is a health-related assessment tool designed for children with allergic diseases. This study aimed to translate the original English version of the Questionnaire to Chinese and to provide psychometric evidence on the validity and reliability of the translated version. DESIGN: Cross-sectional study. SETTING: Out-patient clinic of a non-teaching hospital in Hong Kong. PARTICIPANTS: The Paediatric Allergic Disease Quality of Life Questionnaire was translated to Chinese and then completed by a group of 115 Hong Kong Chinese children (66 male and 49 female; mean age, 11 years) with allergic disease(s). All subjects were asked to respond using visual analogue scales dealing with issues related to the perceived morbidity of allergic diseases. To assess test-retest reliability, 2 weeks later a subgroup of 16 individuals was retested with the same Questionnaire. RESULTS: The internal consistency of the Chinese Paediatric Allergic Disease Quality of Life Questionnaire was satisfactory (Cronbach alpha=0.92). The correlation between the total Questionnaire score and the visual analogue scale score was moderately significant (Spearman's rho=0.49; 95% confidence interval, 0.34-0.62). Structural validity as studied by confirmatory factor analysis found that the structure of subscales was remarkably similar to the original English version. The intra-class correlation between the Questionnaire score from the first and the second test in the subgroup of 16 subjects was 0.75, indicating adequate repeatability. CONCLUSION: The validity and reliability of the Chinese version of the Paediatric Allergic Disease Quality of Life Questionnaire was established for clinical use.

Trends in childhood asthma hospitalisation in three Asia Pacific countries.

AIM: The study aims to examine recent childhood asthma hospitalisation rates in the Asia Pacific countries of Australia, Hong Kong and Singapore. On the background of reported decline in many countries with high asthma prevalence during late 1990s. METHODS: Annual asthma hospitalisation (ICD9-CM: 493 or ICD10-AM: J45-46)* and population data from 1994 to 2008, of children aged 0-14 years old, were obtained from the Australian National Hospital Morbidity Database, from the Hospital Authority in Hong Kong and from the Ministry of Health in Singapore. Data were stratified in two age groups: 0-4 and 5-14 years old, and also in different periods of calendar years. Time-series regression analyses were used to examine temporal trends. Diagnostic transfer was addressed by examining bronchitis hospitalisations. RESULTS: Significant decreases of up to 6.5% per annum in childhood asthma hospitalisation rates were found over the study period. However, the latter half of the study period showed increases in hospitalisation rates in all countries studied. No evidence of diagnostic transfer was found. CONCLUSION: Although there has been a decrease in childhood asthma hospitalisation rates since the 1990s, a modest increase was observed from 2003 to 2008. Ongoing monitoring is required.

Validation of Pediatric Index of Mortality 2 in three pediatric intensive care units in Hong Kong.

OBJECTIVE: To compare the probabilities of death predicted by Pediatric Index of Mortality 2 (PIM2) and Pediatric Index of Mortality 1 (PIM1) models against actual mortalities in 3 pediatric intensive care units in Hong Kong. METHODS: All consecutive patients admitted to pediatric intensive care units in 3 regional non-teaching hospitals between Jan 2006 and December 2006 were included. The data required for PIM1 and PIM2 were collected. The probabilities of death predicted by PIM1 and PIM2 were validated against the actual probability of mortality. RESULTS: Of the 540 patients were included in this study, only seven deaths were observed (1.3%). PIM 1 and PIM 2 overestimated the mortality rate by giving a greater mortality rate. (PIM1: 13.4, Standardized mortality ratio = 0.52, 95% CI = 0.14 to 0.91; PIM2: 14.2, Standardized mortality ratio =0.49, 95% CI = 0.13 to 0.86) The discrimination of PIM1 and PIM2 were satisfactory as reflected by area under receiver-operator characteristic curve of 0.889 (95% CI: 0.703 to 1.000) and 0.904 (95% CI: 0.738 to 1.000) respectively. Calibration was not possible due to insufficient death cases. CONCLUSIONS: The current study showed that PIM2 and PIM1 had similar accuracy in mortality prediction in Hong Kong. The current study also demonstrated the difficulty to calibrate the mortality model when actual mortality rate is low.

Heart rate variability in childhood obstructive sleep apnea.

The identification of patients with obstructive sleep apnea (OSA) is important because of morbidities associated with OSA. A previous adult study demonstrated the use of heart rate variability (HRV) as a tool to identify patients with moderate to severe OSA. Either a reduction in time parameters or an increase in LF/HF ratio was seen at overnight or 24-hr studies suggestive of increased sympathetic modulation. To study the feasibility of daytime HRV as a screening tool, a short-term recording of HRV is studied. Since it was shown in adult study that increased normalized LF, decreased normalized HF and increased LF/HF ratio could be detectable during supine rest at daytime awake period, the authors hypothesize that the differences are also detectable in children. Children who underwent sleep polysomnography for suspected OSA were recruited. Subjects were classified OSA if apnea-hypopnea index (AHI) > 1.5/hr and non-OSA if AHI ≤ 1.5/hr. Continuous 1-hr electrocardiographic monitoring was recorded in awake children during the day. Parameters from time domain and frequency domain were analyzed. Seventy-four male and 17 female snoring subjects were included in this study. Fifty-one (56%) and 40 (44%) of them were classified as "non-OSA" and "OSA," respectively. pNN50, a parameter for parasympathetic modulation, was significantly reduced in the OSA group when compared with the non-OSA group. Using multiple regression, all time domain variables were shown to be decreased in OSA group. Our results suggest that 1-hr study of HRV may be a feasible tool in identifying children with OSA.

Ambulatory blood pressure before and after adenotonsillectomy in children with obstructive sleep apnea.

INTRODUCTION: Hypertension is found to be associated with obstructive sleep apnea (OSA) in both children and adults. But data on the effect of blood pressure after adenotonsillectomy (AT) for children with OSA are limited and controversial. OBJECTIVE: To assess the impact of AT on different parameters of 24-h ambulatory blood pressure monitoring in children with OSA. METHODS: We retrospectively reviewed records of OSA children who had undergone AT and a repeated sleep polysomnography after AT from 2001 to 2008. RESULTS: Forty-four children were identified and included in the analysis. The mean apnea-hypopnea index (AHI) dropped from 14.14+/-15.9 to 3.3+/-7.1. (p<0.001). Twenty (45%) were cured of OSA. After AT, the diastolic BP load decreased significantly. Six out of eight (75%) hypertensive children became normotensive after surgery. For the pre-AT hypertensive group, both systolic and diastolic blood pressure decreased significantly during sleep after AT. However, eight children who were normotensive before AT became hypertensive after AT. These 10 post-AT hypertensive patients were more likely to have post-AT AHI>1 than the post-AT normotensive group, although the difference did not reach statistical significance. CONCLUSION: In the current cohort of OSA children, 44% were cured of OSA and a significant decrease in overall diastolic blood pressure load in 24-h ambulatory blood pressure was achieved after adenotonsillectomy for children with OSA. But hypertension may persist or even occur in those previously normotensive children despite the improvement in AHI. Persistence of OSA may be a risk factor and further study is required. Cure of OSA should not be assumed after AT and follow-up PSG should be performed together with 24-h ambulatory blood pressure monitoring. In light of the current findings, long term study of the blood pressure is warranted for children with OSA.